The invention relates to an apparatus for separating components of mixtures of materials, by means of membrane elements which are spaced mutually apart and superposed, which membrane elements are in the form of pockets, flattened tubes, or the like, and which elements have a bore to allow outflow of the permeate, said apparatus being comprised of:
a feed opening to admit the mixture of materials, and PA1 outlet openings for outflow of the retentate and the permeate,
wherewith in said apparatus the mixture flows in essentially laminar flow along the surfaces of flow chambers for said mixture which chambers are formed between two membrane elements or between a membrane element and a guide element (or redirecting element).
An apparatus of this type is known (Ger. OS 40 30 657). This known apparatus is intended for high permeate flows. The superposed membrane arrangement is mounted in the apparatus with the aid of inner rings which are partially engaged on each side by one of the membrane elements and a drainage structure, respectively. The inner rings serve as spacers between the membrane elements, and in combination with the drainage structures form a superposed membrane arrangement which is resistant to pressure. In applications where the permeate flow is relatively small, wherewith the permeate outflow cross section of the known drainage structure is not fully exploited, the productivity per unit of apparatus volume of an arrangement of this type is unsatisfactorily low, with attendant high costs.